This study hypothesizes that because the arrival of neonatal neutrophils to the site of infection is delayed compared to adult neutrophils, the neutrophils from neonates are impaired in their ability to adhere to and respond to mediators of adhesion expressed on activated endothelial cells. Also, there may be a defect in regulated detachment of neonatal neutrophils that do adhere to stimulated endothelial cells and thus they remain trapped in the lumen of the blood vessel.